This invention relates to a medium feeding device for feeding a medium such as a recording paper, and particularly to a medium feeding device having ribs on a feeding path of the medium. This invention also relates to a guide member including the ribs, and a manufacturing method of the guide member.
A medium feeding device has ribs for guiding a medium along a medium feeding path, as disclosed in Japanese Kokai Patent Publication No. HEI 10-77149. Conventionally, the ribs are formed by injection molding process as is the case with a general plastic product with ribs. In the injection molding process, a molten resin is injected into a mold having cavities formed by electric discharge machining.
However, in order to form high ribs, it is necessary to form deep cavities in the mold. Therefore, the time required for machining the mold becomes long, and the finishing and polishing operation of the mold becomes difficult. Moreover, when the resin is injected in the mold, air (or other gas generated in the mold) may remain in the tips of the cavities. In such a case, the resin may not sufficiently be filled in the cavities, and therefore the defective molding may occur.